This disclosure relates to computer-generated imagery (CGI) and computer-aided animation. More specifically, this disclosure relates to techniques for adding dynamically generated details to animated objects for use in CGI and computer-aided animation.
With the wide-spread availability of computers, computer graphics artists and animators can rely upon computers to assist in production process for creating animations and computer-generated imagery (CGI). This may include using computers to have physical models be represented by virtual models in computer memory. Typically, two-dimensional (2D) or three-dimensional (3D) computer-aided animation combines 2D/3D models of objects and programmed movement of one or more of the models. In 3D computer animation, the first step is typically the object modeling process. Objects can be sculpted much like real clay or plaster, working from general forms to specific details, for example, with various sculpting tools. Models may then be constructed, for example, out of geometrical vertices, faces, and edges in a 3D coordinate system to represent the objects. These virtual models can then be manipulated using computers to, for example, simulate physics, design aesthetic actions such as poses or other deformations, crate lighting, coloring and paint, or the like, of characters or other elements of a computer animation display.
Pixar is one of the pioneering companies in the computer-generated imagery (CGI) and computer-aided animation industry. Pixar is more widely known as Pixar Animation Studios, the creators of animated features such as “Toy Story” (1995) and “Toy Story 2” (1999), “A Bugs Life” (1998), “Monsters, Inc.” (2001), “Finding Nemo” (2003), “The Incredibles” (2004), “Cars” (2006), “Ratatouille” (2007), and others. In addition to creating animated features, Pixar develops computing platforms and tools specially designed for computer-aided animation and CGI. One such example is now known as PhotoRealistic RenderMan, or PRMan for short. PRMan is a photorealistic RenderMan-compliant rendering software system based on the RenderMan Interface Specification (RISpec) which is Pixar's technical specification for a standard communications protocol (or interface) between 3D computer graphics programs and rendering programs. PRMan is produced by Pixar and used to render their in-house 3D animated movie productions. It is also available as a commercial product licensed to third parties, sold as part of a bundle called RenderMan Pro Server, a RenderMan-compliant rendering software system developed by Pixar based on their own interface specification. Other examples include tools and plug-ins for programs such as the AUTODESK MAYA high-end 3D computer graphics software package from AutoDesk, Inc. of San Rafael, Calif.
One core functional aspect of PRMan can include the use of a “rendering engine” to convert geometric and/or mathematical descriptions of objects into images. This process is known in the industry as “rendering.” For movies, other animated features, shorts, and special effects, a user (e.g., a skilled computer graphics artist) typically creates the geometric or mathematical description of objects, such as characters, props, background, or the like, that will used in the rendered image or animation sequence. In some instances, another user (e.g., a skilled articulator or rigger) typically creates a number of animation control variables (avars) for manipulating the objects. In further instances, yet another user (e.g., a skilled animator) typically uses the avars to pose the objects within the image or sequence and specify motions and positions of the objects over time to create an animation.
In other instances, objects may be too complex or the number of objects may be too large for a user to manipulate individual. As such, the production of CGI and computer-aided animation may involve the use of simulations and other dynamic techniques to specify motions and positions of the objects over time to create an animation. One of the challenges in creating visually appealing images of objects whose motions and positions are determined by simulations can be the balancing of a desire for a highly-detailed image of an object with the practical issues involved in allocating the resources (both human and computational) required to produce the highly-detailed image.
Accordingly, what is desired is to solve one or more of the problems relating to adding dynamically generated details to animated objects for use in CGI and computer-aided animation, some of which may be discussed herein. Additionally, what is desired is to reduce some of the drawbacks relating to adding dynamically generated details to animated objects for use in CGI and computer-aided animation, some of which may be discussed herein.